Rent Shop Volunteer Join

Q. Who is Mr. Smarty Plants?

A: There are those who suspect Wildflower Center volunteers are the culpable and capable culprits. Yet, others think staff members play some, albeit small, role. You can torture us with your plant questions, but we will never reveal the Green Guru's secret identity.

Help us grow by giving to the Plant Database Fund or by becoming a member

Did you know you can access the Native Plant Information Network with your web-enabled smartphone?

Share

Ask Mr. Smarty Plants

Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.

Search Smarty Plants
See a list of all Smarty Plants questions

Please forgive us, but Mr. Smarty Plants has been overwhelmed by a flood of mail and must take a break for awhile to catch up. We hope to be accepting new questions again soon. Thank you!

Need help with plant identification, visit the plant identification page.

 
rate this answer
1 rating

Wednesday - September 21, 2011

From: Abilene, TX
Region: Southwest
Topic: Diseases and Disorders, Trees
Title: Live oak trees with rusty spots and holes on tree trunks
Answered by: Nan Hampton

QUESTION:

I have live oak trees that have developed rusty spots, small holes on the tree trunks and sawdust on the trees base. They were planted in Oct 2010. We have had a hot dry summer in Texas this year and I am not sure if this is due to the extreme hot weather. Please advise.

ANSWER:

The principal disease associated with Quercus fusiformis (Escarpment live oak) is oak wilt.   As you can read on the species page on our Native Plant Database:

"...it is susceptible to live oak wilt and live oak decline when stressed by drought, so care must be taken to protect it from injury both aboveground and below ground to prevent infection."

Certainly, your trees have experienced the stress of extreme drought and high temperatures. I don't know if your trees are infected by oak wilt, but it is certainly possible.  You can see on this map from the Texas Oak Wilt webpage that Taylor County has been confirmed as having oak wilt.  You can see the characteristic leaf browning pattern associated with Texas oak wilt on the Texas Oak Wilt Information Partnership page. Contact the Taylor County Office of the Texas AgriLife Extension Service to see if you can arrange to have someone look at your trees to determine if you do have oak wilt.  You could also consult a professional arborist.  You can search for a Certified Arborist in Abilene on the International Society of Arboriculture page. The Texas Oak Wilt Information Partnership page has a wealth of information about diagnosing, treating and preventing oak wilt.

Another disease that can affect oak leaves is Tubakia (formerly known as Actinopelte) but it is usually a disease associated with wet years which certainly doesn't apply to this year.  For insect pests, you can read Insect Pests of Central Texas Forests to learn that nitidulid beetles are responsible for spreading the fungus, Ceratocystis fagacearum, that causes oak wilt and that stressed trees are often attacked by wood borer insects and oak bark beetles. 

Whatever you trees are suffering from, there is no doubt that they have been seriously stressed by the heat and drought conditions.  You might also read "Continuing Severe Drought Conditions Will Seriously Harm Trees" from the Texas Forest Service.

 

More Trees Questions

Is Robinia pseudoaccia a good replacement tree for Shumard oaks in Austin TX?
February 27, 2013 - Recently two of our Shumard trees in the front of our house died. Both trees were small/medium in size having only been growing for 13-17 years. I've been reading about Black Locust trees which accor...
view the full question and answer

Bald cypress causing problems in Spring TX
June 22, 2010 - There is a 50+ ft Bald Cypress growing near my property line. While the tree has grown substantial knees along the driveway and some as far as 35 ft from the tree in my flower beds, I do not see any d...
view the full question and answer

My newly planted Redbuds are not doing well.
June 24, 2009 - I ordered and received 2 Red Bud trees from one of the popular ordering houses. They explained that they were dormant and not dead, and gave us instructions on how to plant them, which we followed. Th...
view the full question and answer

Galls on live oak trees in Austin, TX
April 14, 2005 - I am a resident of a condominium complex in Austin that has numerous Live Oak trees. Can you explain what the gall type things are hanging from the trees at this time of year and all over the grounds?...
view the full question and answer

Bugs on Arizona Cypress in Bellwood IL
August 27, 2011 - I live in Illinois and have an Arizona Cypress that looks like it is dying but I notice today it has bugs inside its cone. Can you tell me why and what can I do?
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.